Improve check whether an URL exists

CREDITS.md

@@ -171,12 +171,6 @@ The following list credits all third-party resources used in the Fictioneer them
   License: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/)<br>
   Source: https://stackoverflow.com/a/17508056/17140970
 
-* **Check whether an URL exists**<br>
-  Copyright: aman neekhara<br>
-  License: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)<br>
-  Source 1: https://auth.geeksforgeeks.org/user/aman%20neekhara/articles<br>
-  Source 2: https://www.geeksforgeeks.org/how-to-check-the-existence-of-url-in-php/
-
 * **Add columns in admin view**<br>
   Copyright: Misha Rudrastyh<br>
   License: [GPLv2 or later](https://www.gnu.org/licenses/gpl-2.0.html)<br>

functions.php

@@ -6,7 +6,7 @@
 
 function fictioneer_display_execution_time() {
   // Abort on AJAX
-  if ( defined('DOING_AJAX') && DOING_AJAX ) {
+  if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) {
     return;
   }
 

includes/functions/_utility.php

@@ -17,24 +17,20 @@ if ( ! function_exists( 'fictioneer_url_exists' ) ) {
    */
 
   function fictioneer_url_exists( $url ) {
-    if ( ! $url ) {
+    if ( empty( $url ) ) {
       return false;
     }
 
-    $curl = curl_init( $url );
-    curl_setopt( $curl, CURLOPT_NOBODY, true );
+    $response = wp_remote_head( $url );
 
-    if ( curl_exec( $curl ) ) {
-      $statusCode = curl_getinfo( $curl, CURLINFO_HTTP_CODE );
-
-      if ( $statusCode == 404 ) {
-        return false;
-      }
-
-      return true;
+    if ( is_wp_error( $response ) ) {
+      return false;
     }
 
-    return false;
+    $statusCode = wp_remote_retrieve_response_code( $response );
+
+    // Check for 2xx status codes which indicate success
+    return ( $statusCode >= 200 && $statusCode < 300 );
   }
 }